ACKNOWLEDGMENTS Personnel of the Reynolds Electrical and Engineering Company at the Nevada Test Site have been most cooperative in taking samples for investigations. Particular thanks are extended to Mr. D. L. Wireman and Mr. C. E. Rosenberry, Jr., for their constant help during the course of investigations. Mr. E. R. Eastwood of this laboratory is also gratefully acknowledged for his painstaking effort in performing the laboratory analysis. Dr. E. A. Bondietti and Dr. R. C. Dahlman have helped the author by the many stimulating discussions on environmental behavior of plutonium. 14